Managing astringency in coffee brewing

10 Minutes With Helena Oliviero: Part One

We talk with coffee champion and Q Grader Helena Oliveriero about her career, her life in Colombia, and what it means to be a young woman in the male-dominated coffee world.   BY TANYA NANETTISENIOR ONLINE CORRESPONDENT Featured photo courtesy of Helena Oliviero Helena Oliviero, originally from Tuscany, Italy, is 28 years old, but already she […]


What I Learned from My First Tea Ceremony

After taking in a brief moment of a tea ceremony in Thailand, I finally had the chance to participate in the full experience recently in Malaysia. BY TANYA NANETTI SENIOR ONLINE CORRESPONDENT Photos by Tanya Nanetti In the years that I worked as a barista in a café, tea always played a marginal role in […]


3 All-Women Coffee Roasting Companies that Are Changing the Game

The world of specialty coffee is still largely governed by men, but these all-female specialty-coffee roasters are helping to close the gender gap. BY TANYA NANETTISENIOR ONLINE CORRESPONDENT Feature photo courtesy of Lot Zero/7Gr As is the case for many commercial sectors, the world of specialty coffee continues to display gender disparity along the entire […]


5 Amazing Coffee Drinks in Reno, Nev.

Here are some standout specialty drinks you can try in the Biggest Little City in the World. BY EDDIE P. GOMEZSPECIAL TO BARISTA MAGAZINE Photos by Eddie P. Gomez Reno, Nev., has more cafés per capita than just about any other place in North America. And because it is a snowier-than-usual winter in northwestern Nevada […]

Managing astringency in coffee brewing

Brewing at Home and On the Road with Darrin Daniel

We check in with the Cup of Excellence executive director to learn his current coffee-brewing habits. BY TANYA NANETTISENIOR ONLINE CORRESPONDENT Featured photo by Emre via Unsplash Brewing coffee is, for many coffee professionals, more than just a job.   They usually brew coffee every day, both for themselves and their customers. Perhaps they do it […]


Know Your Sweeteners: Honey: Part One

Not all sweeteners are made equal! In this series, we’ll take a closer look at different types of sweeteners and syrups—starting with honey. BY EMILY JOY MENESESBARISTA MAGAZINE ONLINE Featured photo by Arwin Neil Baichoo via Unsplash Though you can’t go wrong with simple syrup or the tried-and-true vanilla, there are many options when it […]


Understanding the Process: Koji Fermentation

Continuing our series on coffee processing, we learn about koji fermentation, a unique process usually associated with the brewing of sake. BY TANYA NANETTISENIOR ONLINE CORRESPONDENT Photos courtesy of Forest Coffee If brewed properly, a cup of coffee can offer countless variations of flavor and aroma. The quality and complexity of these attributes depend on many different […]


Test Drive: Update Your Grinding With More Comandante Grinder Accessories

The popular hand grinder has more to offer with a new line of tools and accessories now available. BY TANYA NANETTISENIOR ONLINE CORRESPONDENT Feature photo by Tanya Nanetti To brew the perfect cup of coffee, it’s important to choose the right coffee equipment. One essential is a reliable coffee grinder. Most coffee lovers start with a […]

Managing astringency in coffee brewing

Managing astringency in coffee brewing

minimum dose size?

I use the Hario switch to brew my coffee and am trying to reduce my caffeine consumption. Hence I would like to brew smaller cups of coffee. I am currently using 10g of coffee with 160g of water. (1:16 Ratio) I am wondering if there is a minimum amount of coffee...

Managing astringency in coffee brewing

I’ve frequently written about astringency on Instagram and Jonathan Gagné, author of the forthcoming book The Physics of Filter Coffee, wrote an excellent blog post about the science of astringency. Here I’d like to offer a practical guide to finding and fixing astringency in brewed coffee.

What causes astringency in coffee?

Large molecules called polyphenols, in particular chlorogenic acids (CGAs) and tannins, are the likely, primary sources of astringency in brewed coffee. Being larger molecules, polyphenols tend to extract less readily than most other coffee solubles, though CGAs seem to extract more readily than tannins do. (It has not been scientifically proven that CGAs extract more readily than tannins do, but it seems probable.) It’s likely the majority of astringent polyphenols found in brewed coffee extract via channeling in percolation brewing. Astringency is much less likely to occur in immersion brewing due to the lack of channeling.

What increases the risk of an astringent brew?

There are several potential sources of increased astringency in brewed coffee:

  • beans (seeds) from underripe cherry*

  • underdevelopment in roasting*

  • channeling during percolation brewing

*Both underripe cherry and underdeveloped roasts tend to yield higher levels of CGAs in the cup. CGAs are both astringent polyphenols and also the most prevalent acids in coffee. Having some CGA is probably important for a delicious cup (though I’m not sure any of us have ever tasted a coffee without any CGAs), but when the CGA level is too high, the coffee becomes noticeably astringent.

How to find and fix the source of astringency

When I find a brew astringent, I go through a series of steps to find and fix the source of the astringency:

  • If I have previously made a non-astringent, percolation brew of the same roast batch of the coffee in question, it is almost certain that channeling caused the astringency in the more recent brew. In that case, I would brew again with either (hopefully) better technique of a coarser grind setting.

  • If I cannot rule out channeling (for example, if I don’t trust my brewing method or skill), I will taste the coffee as a cupping. If the cupping is astringent, then channeling was not the cause, or at least not the only cause, of the astringency in the percolation brew.

  • If both percolation and immersion (cupping) produced astringency, the cause must be due to an underdeveloped roast or underripe cherry.

  • If some roast batches of the coffee in question are astringent and others aren’t, it is likely that roast development was the cause of the astringency.

  • If all roast batches of the coffee are astringent when cupped, and you are confident they are not all underdeveloped, then the green was likely from underripe cherry.

Shopping cart0
There are no products in the cart!
Continue shopping
0